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By Steve Stiles
Geographic Range
Harp seals are found in the Arctic and Atlantic ranging from the Kara and Berents Seas to the waters surrounding Greenland and Newfoundland. There are 3 populations of harp seals: one that breeds in the Gulf of St. Lawrence off the coast of Newfoundland, another that breeds north of Jan Mayen island in the Greenland Sea, and a third that breeds in the White Sea.
Biogeographic Regions:
nearctic 
(native ); arctic ocean (native ); atlantic ocean (native ).
Habitat
Harp seals live in the open sea on the edge of the pack ice. They are dependent on the ice for breeding and molting. They prefer rough, hummocky ice at least 25 cm thick, and they maintain natural holes 60-90 cm in diameter for purposes of access to water and breathing. During the breeding season, up to 40 seals may share a breathing hole.
These animals are found in the following types of habitat:
polar ; saltwater or marine .
Terrestrial Biomes:
icecap.
Physical Description
(286 to 352 lbs)
(6.56 ft)
Harp seals can grow up to 2 meters in length and 160 kg in weight, with females being slightly smaller in size than males. Males are silver gray with black heads and black "horseshoe" or "harp-shaped" markings on their backs. Females are paler color and have markings that are less distinct. Often the color of females is broken up into spots. Usually, the coloration of the seals changes with age. In April and May, harp seals shed their coats and grow new ones.
Some key physical features:
endothermic ; homoiothermic; bilateral symmetry .
Sexual dimorphism: male larger.
Reproduction
Males fight for access to females by using their teeth and flippers. Mating occurs on the ice and the seals are monogamous for the season.
Mating systems:
monogamous .
Sexual maturity is reached in males at 6 years and in females at 5 years. The reproductive season for harp seals is from the end of February to the end of March. The seals migrate south to breed and molt. Gestation lasts 11.5 months, with 4.5 months dormancy of the fertilized ovum (delayed implantation). Females give birth to one pup, occasionally to twins. The pups weigh about 10 kg and are suckled for about 12 days. The milk is rich in fat and mostly becomes blubber. Pups can gain up to 2 kg a day. During lactation, the mother feeds on little if anything at all. After weaning, the young spend up to 10 days alone until their embryonic hair is replaced by proper fur.
Key reproductive features:
iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; viviparous ; delayed implantation .
Behavior
Harp seals are solitary animals except during breeding season, when tens of thousands of individuals come together. There is no social organization in these aggregations. The seals seem to be seasonally monogamous. They migrate south in autumn and retreat north in summer with the receding ice pack. The migration can total 6,000-8,000 km. Harp seals are powerful high-speed swimmers capable of moving quickly on the ice and diving to depths of over 900 ft.
Key behaviors:
natatorial ; motile ; migratory ; solitary ; social .
Communication and Perception
Their senses of vision and hearing are very acute, especially under water, while their sense of smell is not so acute.
Communicates with:
acoustic .
Food Habits
Harp seals are carnivorous. They feed on fish, and crabs and other invertebrates. The fish taken include capelin, arctic cod, cod, herring, and halibut. Small crabs are the primary source of food after weaning.
Animal Foods:
fish; mollusks; aquatic crustaceans.
Predation
- large sharks (Chondrichthyes)
- killer whales (Orcinus orca)
Harp seals are eaten by sharks and killer whales.
Economic Importance for Humans: Positive
Harp seals are second only to fur seals in commercial value. Hunters kill them for fur, oil, and leather. Native peoples of the north kill 10,000 seals a year for food and fiber.
Ways that people benefit from these animals:
food ; body parts are source of valuable material.
Conservation Status
Although there are large number of these seals, many are killed by hunters each year. Currently, the population is over 2 million.
Contributors
Steve Stiles (author), University of Michigan.
